Evergreen grasses : to cut or not to cut?

Unlike their deciduous cousins, which once established can be cut right down to the ground in late winter/early spring, evergreen grasses grow throughout the seasons so they won’t thank you for treating them in the same way. Here are three of the several evergreens I grow, each is groomed in different ways according to the instructiions on their care labels. Given the right conditions none are hard to grow, I’ve rated the annual effort it takes to keep them looking good.

Chionochloa rubra : easy

Chionochloa rubra is the lowest maintenance grass I grow, since planting it in 2011 I haven’t laid a finger on it. Chilly weather enhances the foxy-red tints in its foliage. Thatchy strands blend in, as do spent flowering stems.

Last year this group flowered rather inconspicuously for the first time alongside the opium poppies and red valerian. Noticeably, in mid-summer, tussocks look greener than in winter.

Unlike many grasses Chionochloa rubra doesn’t divide happily, let alone romp away. Five years ago a 0.5 litre division struggled to establish, this is what it looks like today. At a third of the size of the ones bought as larger plants from Pan Global Plants a year later, this is slow progress.

Admittedly, conditions are much more favourable down in the sheltered yard, the plants growing in gravel in an open sunny spot are much stronger as a result. Even so, I’d hesitate to risk one of these tightly bunched mature specimens. So far, seed hasn’t germinated. All of which suggests that sourcing good-sized plants from a specialist nursery is a sound investment.

Stipa gigantea : medium

These days I’d say Stipa gigantea is a close second to being ultra-low maintenance. Since finding them a sunny, sheltered, and spacious spot in well-drained soil they’ve thrived on very little attention from me. Having sulked in four other positions in this as well as my last garden, I’d almost given up on them. Since 2012 the original three at the front of the border did so well that I added a further five in 2013.

Much earlier in the year, planted a metre apart on centre allows room for clumps of Iris sibirica ‘Tropic Nights’ to be squeezed in between them, both flower early in May so any tidying of the stipa has to be done sooner rather than later in the spring. There’s not much to do, the flowering spikes fall by December here, which only leaves snipping out the woody stubs of last year’s stems in early April. If they’re looking thatchy I might lightly rake them through either using a spring tine rake or by running my hands through from the base of the plant. Stipa leaves are leathery, for me gloves are a must. Showa gloves are great for gently grooming grasses by hand, designed to be slightly tacky loose leaves stick to them. Three of these plants are now in their twelfth year, remarkably they’re still looking good, I’d expect them to be getting a little bald and nobbly in the centre. I haven’t tried it, but I’m told mature clumps divide well.

Second year seedlings April 2016

To my utter delight and amazement, the once miserable plants self-seed profusely now. The above images of seedlings lifted from the gravel path were either potted-up or planted in a nursery bed last spring. Seedlings take two years to grow a good root system, only then do they make sturdy plants for spacing in the border. Until then they’re top-heavy and, although stipa doesn’t like to be overcrowded, they work well from a young age with early summer flowering bulbs like alliums. Stipa gigantea comes in a range of sizes, from the shortest ‘Pixie’ to the tallest ‘Gold Fontaene’, last year Neil Lucas introduced ‘Goldilocks’ which is of medium height.

Anemanthele lessoniana : harder

Perhaps it’s the third of the evergreens that’s trickiest to grow well. The regime can seem complicated, especially where greater numbers of plants are involved. Anemanthele is a stunning subject for mass planting but as a short-lived New Zealand native the key is a steady supply of new plants. Fifty of them are planted a metre apart formimg a low hedge beside the drive which then curves back in a loop around the Acer griseum. Planted in three waves, they don’t need replacing all in one go. This grass doesn’t flower fully until its third year, after which a steady supply of seedlings are available to keep the structured planting going.

Summer

Late winter

Early spring

It took me a while to work out that young plants thrive best on relative neglect while older plants can be treated more ruthlessly. Part of my winter reading was Lawrie Metcalf’s The Cultivation of New Zealand Native Grasses. I was whooping in agreement when I read his authoritative cultivation notes : anemanthele should never be cut right back to ground level. The veteran group above planted around the acer are due for retirement next year – April 2016 was their last haircut. I reduced them by 30%.

In our exposed garden overwintering foliage tips are first tinted, then dried by frosts as well as by desiccating winds, cutting them back too soon risks the new foliage too. Prolonged cold and wet spring weather can also put off them off. This year the younger and more vigorous row beside the more sheltered cedar path were cut back by 50%. For a while the blunted ends may look unsightly but as long as the tightly bunched foliage is green and lush the plants should recover.

Once the centre of the plant looks this thatchy it’s time to replace them with seedlings coming into their third year. I don’t mind the extra bit of work because between the third and fifth year the impact of the continuous mass of flowers is sublimely beautiful.

Spent day lily stems in a mass of anemanthele inflorescence

The longevity of grasses versus their seeding or growth habits fascinates me, I can see that some are much lower maintenance for being truly perennial than others. For me short-lived, free-flowering, self-seeding grasses are useful, even if their habits have to be controlled. In 1998 Metcalf warned that in optimum conditions NZ landscapers should be aware of anemanthele’s propensity to become a self-seeding nuisance, the gossamer sprays of infloresences are loaded with fine seed held on arching wiry stems intent on being tracked by hoof or boot rather than being windborne. In a garden setting this makes it easier to deal with unwanted seedlings.

To curtail wayward seedlings I deadhead anemanthele, preferably on a damp day before the seed sets. I also site them where either the mower or passing cars will check their spread. Come spring I hunt out the remaining seedlings, they’re usually huddled close to the parents, then pot them up.

Brian Skeys tip – dog comb

It works.

Based on my experience, anemanthele does well for at least five years, more perhaps depending on the conditions in which it’s grown. Above is the runt of the driveside plants, ticking over in a very inhospitable spot this one deserves a little extra TLC, hence time with a wide-toothed dog comb. Anemanthele is a likeable chameleon, in a dry sunny spot the orange tints are sharpest, in damp shade foliage is more olive-green. In either extreme flowering seems to be restricted. Come summer I move first-year seedlings into a shady spot in the nursery area, second-year seedlings are grown on in a shadier nursery bed.

Imagine hundreds drifting down a sunny slope ….

Brian Skeys also grows grasses, among them beautiful Chionochloa rubra. Thanks to a top-tip from him I’ve recently discovered an inspirational planting of this easy-going grass in Devon. Googling Chinonchloa rubra along with The Garden House will transport you to designer Sophie Dixon’s oh so tempting images of what can be achieved planting this grass en masse. Alas, I don’t have an extensive sheltered, sunny slope for such an ambitious planting here, a late summer sortee to Buckland Monachorum will have to do. Meanwhile, I shall enjoy the small group of zero maintainance grasses planted in the sun trap of the yard.

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27 thoughts on “Evergreen grasses : to cut or not to cut?”

Stipa gigantea is my favourite grass, with the sun shining through it, it is just like spun gold! I’m so glad that it is doing well in the garden here, we now have two, but who knows, maybe I’ll have to add another!

What an evocative description, Pauline your Stipas sound very happy in your garden. If you get a third which one will you try? I like the sound of ‘Goldilocks’, I wonder if it might do well in a large planter?

This is very useful again, Kate. I’ve been debating whether to cut back the pheasant grass that I moved a few weeks ago. It got a bit stressed immmediately afterwards and no longer looks lush. I think I will take it down to a third like your older plants.

It’s been quite dry recently, maybe keep it well watered? Trimming off the top growth won’t hurt, it may even help perk it up. All of mine started to look less lush from mid Feb, just the bad weather I think. They were perfect until then! Good luck with yours.

Five would look amazing! If you’ve space between plants, Iris sibirica work nicely as a long term, early flowering combination – both are usually on sale on the same time of year. Wisley had some good sized pots of SG a few years ago.

Great post Kate. Lovely photographs too. All I know about grasses could be written on a single blade, so I found this fascinating. I once grew Stipa gigantea but it died in the first winter – I suspect it was too damp where I planted it. I now want to try again, but will see how I go with my pot of Imperata cylindrica ‘Rubra’ and build up my confidence from there :-)

Thank you, Dan, I’m glad you like it. I love Japanese Blood Grass, just gorgeous and good for a pot. I hope yours does really well for you and encourages you to try other grasses. Carex solandri is a wonderful, pot friendly, dead easy evergreen sedge, it would look stunning in the back row of your spring bulb theatre (;.

Of my seven recently moved Anemanthele interestingly it is the older ones that I cut back that are settling in the best. They’ve put on about four inches of new growth already. The younger ones have gone brown at the tips and I’m thinking they should have a light trim. Now I need to get the succession going and replace the oldest each year. So glad I put them all together having seen your photo of the mature ones en masse.
Chionochloa rubra next..

Good to hear the more mature ones have transplanted well, there’s been quite a bit of frost here over the last few weeks – just looking at magnolias in the garden today, lots of blooms have been burnt. Fingers crossed your youngsters will perk up soon with some TLC and as the nighttime temps improve. C.rubra would look fabulous spilling down your slope!

Most interesting post Kate with lots of practical information – and some lovely photos of sun on your grasses. I shall definitely have to get a dog comb or two, especially after having just been recommended them for cleaning paintbrushes!

Thank you Cathy, that’s a great idea – I shall try a dog comb on the paintbrushes. I think it would work well on tough leaved carex too, I have some pot grown green leaved Frosted Curls that are looking very sorry for themselves right now.

How interesting, Kate. I’ve also planted S. gigantea in different places with varying success. Don’t think they like it too dry either in summer. Chionochloa looks very pretty and I’ve just noted it. Maybe good for a container too. Beautiful images!

Thank you Annette, I’m pleased you like the look of the less often seen C.rubra. The Garden House images are worth checking out for an idea of the full size at maturity 4’x3′ (especially if thinking about pot growing). There’s a garden in N.Ireland where they make good specimens in big planters. If I can find the name of it I’ll get back to you.

Thank you Kate for another interesting and informative post. It is useful to know which ones to cut back and when. I have always grown and loved grasses but I have never seen them displayed en masse and looking as wonderful as in your garden. It makes me want to be more adventurous with them. I am going to Beth Chatto’ s tomorrow so I shall be on the look out for some more. By the way have you ever grown my favourite Miscanthus nepalensis? Unfortunately it is not hardy in my garden, so it is one I loved and lost.

Miscanthus nepalensis is a favourite of mine, I grow a few. Recently I was given Crug Farm’s cultivar M.n.’Shikola’, this and Pan Global Plants one are meant to be hardier. It will be exciting to see how they vary. I did write a post on Himalyan Fairy Grass as it’s also known – the star plant is in my neighbour’s garden. Have a lovely trip to Beth Chatto’s garden and nursery – both great for grasses, of course!

Our last winter was the longest and wettest in a long time – perhaps 10 years – and for the first time I felt that a mere combing of my Anemanthele lessoniana clumps wouldn’t be enough, so I cut them back in early spring. As an experiment, I went against all the recommendations I’d read and cut a couple right down to the ground, and to my surprise they are the ones that are looking the best now: all lush, fresh growth, in contrast to the still convalescent look of all the other clumps. Just thought I’d share this.

Now a question. I have four mature Stipa gigantea, all of which I started from seed four or five years ago. They look fantastic, but except for one of the clumps – which also happens to be the largest – the others have a fairly large number of flowering culms that seem to die at different stages before they are fully grown, and the ‘aborted’ seed heads on those culms look dry instead of coppery, and the culms break easily and look like it’s already mid-winter. Does the same happen with some your S. gigantea clumps? If so, would you have any idea what the cause might be?

Hi Erik, thank you for your most interesting comments on this post. It sounds as though you take a keen interest in grasses too.

Re anemanthele : even within the UK certain grasses perform differently so require different maintenance, especially at the juvenile stages – I got away with a lot more growing them in London than I do here on the (winter-wet) Welsh borders. I have cut scruffy 3-5 year olds down to ground level, rarely do I enjoy the success you describe in your garden.
Re Stipa : if all four plants enjoy the same site/conditions but one of them shows predominantly stalled flowering stems, do you think that you’re noticing the difference between variable seed grown plants? Also, it may depend on which form the seed came from…. I think a really good mature specimen of this grass shows how it is an over-achiever in that it produces masses of them, my best specimen (Pagel’s fabulous Klein Fontaene)looks like a perfect globe of inflorescences. In late spring I can see that only a few of them seem to stall at a certain point as you describe – probably in response to light/heat/seed production. I have heard that there’s an RHS trial of Stipa gigantea in the pipeline, there have been a number of new introductions like ‘Goldilocks’ and ‘Pixie’, I wonder if this will come up?

Yes, I had considered natural variability, as well as soil & moisture (not exposure, because they are all in full sun). The largest tussock – the one with very few ‘stalled’ culms – is growing in soil with more organic matter than the other three, so probably richer and less dry in summer. From all I’ve read, S. gigantea does well in poor soil and is extremely drought tolerant, so it would seem to me that the ones in leaner, drier soil should actually do better.

I am at once tempted to replace the three under-performing plants with seedlings of the best one – they all self-sow with abandon around my garden – and reluctant to replace mature plants that have taken years to reach that point with open-pollinated seedlings that are not guaranteed to perform like their better parent.